The Effect of Unintended Facet Arthrodesis on the Treatment Outcome of Dynamic Neutralization System for Lumbar Degenerative Diseases.

Purpose: This study aimed to examine the influence of unintended facet arthrodesis on the therapeutic effectiveness of the dynamic neutralization system (Dynesys). Methods: This retrospective study enrolled consecutive patients who underwent posterior decompression and dynamic stabilization for lumbar spondylosis or spinal stenosis. Follow-up assessments included lumbar radiography, lumbar vertebral computerized tomography (CT), visual analog scale (VAS), and Oswestry disability index (ODI). Patients were classified into the facet fusion and non-fusion groups. The differences in the VAS scores for back pain and leg pain, ODI, intervertebral range of motion (ROM) at the surgical segments, and upper adjacent segments were assessed before and after treatment. Results: A total of 49 patients (29 males and 20 females) aged 31-65 years were enrolled and followed-up for over 40 months. Among the patients, 16 (32.7%) experienced unintended facet arthrodesis and were assigned to the fusion group, whereas the remaining patients were assigned to the non-fusion group. There was a significant increase in the incidence of facet arthrodesis in the surgical segments over time post-surgery (χ2 = 6.2, p < 0.05). The ROM of the surgical and upper adjacent segments, VAS scores for back pain and leg pain, and ODI were all significantly different before and after the operation (p < 0.05), but not between the fusion and non-fusion groups (p > 0.05). Conclusion: Although unintended facet arthrodesis is common after Dynesys procedure, the presence of facet arthrodesis does not significantly affect the efficacy of Dynesys in treating lumbar degenerative diseases.

Morphologic Changes of Intervertebral Foramen After Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Radiographic and Clinical Study.

OBJECTIVE: We aimed to investigate the morphologic changes in the intervertebral foramen after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and analyze the necessity of routinely performing contralateral intervertebral foraminal decompression in degenerative lumbar spondylolisthesis cases with bilateral symptoms. METHODS: 72 single-level degenerative lumbar spndylolisthesis patients with bilateral symptoms were included, all of whom underwent unilateral approach MIS-TLIF. Preoperative and postoperative foraminal height (FH), foraminal width (FW), disc height (DH), distance from existing nerve root to upper edge of lower pedicle (RTP), and contralateral side spinal canal area (CSCA) were measured at surgical and contralateral side. Clinical outcomes were evaluated using the visual analog scale, Oswestry Disability Index, and Japanese Orthopaedic Association score. RESULTS: The preoperative values are comparable between operative and contralateral sides (P > .05). The postoperative values for FH on operative and contralateral sides were 16.23±2.48 mm and 16.10±2.42 mm, for FW were 11.36±2.58 mm and 11.31±2.71 mm, for IH were 8.18±1.58 mm and 8.42±1.54 mm, for RTP were 8.58±1.26 mm and 9.14±1.77 mm, and the CSCA of the spinal canal on the contralateral side were 211.59±48.12 mm², respectively. The difference between these was also not statistically significant (P > .05). The values increased significantly on the surgical and contralateral side (P < .05). The visual analog scale for low-back and leg pain, Japanese Orthopaedic Association, and Oswestry Disability Index improved significantly at 2-year follow-up. CONCLUSIONS: Unilateral MIS-TLIF can effectively improve contralateral FH, DH, FW, RTP, and CSCA. It is not necessary to routinely perform contralateral intervertebral foramen decompression in degenerative lumbar spondylolisthesis with bilateral symptoms when symptoms are mild on one side.

Diagnostic value and clinical significance of magnetic resonance imaging with the FS-PD-TSE sequence in diagnosing lumbar cartilaginous endplate failure.

PURPOSE: The aims were to use magnetic resonance imaging (MRI) to compare the efficacy of fat-suppressed proton-density turbo-spin-echo (FS-PD-TSE) images and T1-weighted (T1WIs) and T2-weighted images (T2WIs) in identifying cartilaginous endplate failure (CEF), and to propose a modified Rajasekaran classification based on the FS-PD-TSE sequence. METHODS: Thirty-one lumbar disc herniation (LDH) cases were enrolled. Totally, 155 discs and 310 endplates were evaluated by MRI with T1W, T2W, and FS-PD-TSE sequences. Disc degeneration (DD), LDH grades, and the total endplate score (TEPS) of CEF were evaluated. Chi-square, Spearman rank correlation analysis, and multiclass logistic regression were used to compared the sensitivity in diagnosing CEF. A modified Rajasekaran classification based on FS-PD-TSE sequence was established to diagnose CEF. The multiclass logistic regression model was used to analyse the relationship between modified Rajasekaran classification and DD and LDH. RESULTS: There were 117 (75.5%) segments with CEF in T1WIs, 115 (74.2%) in T2WIs, and 127 (81.9%) in FS-PD-TSE, respectively. Chi-square test showed FS-PD-TSE images were more sensitive than T1WIs and T2WIs (P < 0.05). Spearman rank correlation analysis revealed a significant correlation between TEPS and LDH and DD in T1WIs, T2WIs, and FS-PD-TSE images (P < 0.05). A multiclass logistic regression model showed that the incidence of DD and LDH significantly increased accordingly with increases in modified Rajasekaran classification (P < 0.05). CONCLUSION: The FS-PD-TSE sequence has high diagnostic value for lumbar CEF. CEF is a risk factor for LDH. The new classification for lumbar CEF based on the FS-PD-TSE sequence has good predictive ability for LDH and DD. These slides can be retrieved under Electronic Supplementary Material.

Influence of contoured versus straight rod on clinical outcomes and sagittal parameters in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) at L4/5 level-more than 5 years follow-up.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is among the most commonly performed surgical procedure to treat lumbar degenerative disorders. In open TLIF procedure, usually rods were contoured to restore normal lumbar sagittal alignment. However, in MIS-TLIF procedure, contoured rods sometimes were easier to rotate and harder to be locked at the satisfactory position due to instrumentation design and limited exposure. Thus, straight rods had been used in single-level MIS-TLIF in our institution. However, the effect of rod contouring on sagittal parameters and clinical outcomes remains unclear. In the present study, we aim to evaluate the effects of single-segment MIS-TLIF with contoured versus straight rods on sagittal parameters and clinical outcomes. METHODS: A retrospective review of MIS-TLIF at L4/5 was performed between 2009 and 2013 in our hospital. Seventy-six cases were divided into contoured rod group (CR group, n = 35) and straight rod group (SR group, n = 41). Clinical outcomes and radiographic measurements at five years' follow-up were evaluated by visual analog score (VAS), Oswestry disability index (ODI) and Japanese Orthopaedic Association (JOA) score, spino-pelvic parameters, disc height and fused segment angle. Fusion rate and cage subsidence were also measured. RESULTS: Preoperative VAS, JOA, ODI and radiographic parameters were comparable between two groups. The average follow-up was 63.72 ± 3.86 months. VAS, JOA and ODI were significantly improved at 5-year follow-up in both groups, and there were no significant differences between two groups(P > 0.05). Fused segment angle (FSA) was greater in CR group than SR group (P = 0.024), while the other radiographic parameters were not significantly different(P > 0.05). Rod process, fusion rate and cage subsidence were not risk factors of post-surgical malalignment, patients with pre-surgical sagittal imbalance was more prone to show post-surgical malalignment (P < 0.05). CONCLUSIONS: Both CR and SR groups acquired satisfactory clinical results. Although contoured rods had better fused segment angle, contoured or straight rods at single L4/5 level had little effect on global spino-pelvic parameters and clinical outcomes in a 5-year follow-up.